AVX-720 Not working..

hello all,

I recently had my car in the shop ( new transmission ) for about a month, they also replaced my battery as it is old. In the car i have JVC AVX-720. When i got the car back, the only thing that was working is the power button is lit up (pressing it does nothing) , and it plays very low music. None of the buttons on the front are lit up, nevermind working. And the LCD screen does not turn on either ( When the unit has power though it has faint horizontal black lines going across it. Also, when i plug my ipod in it seems to go back and forth charging.
If anyone has any input about what could be going on, I would appreciate it.